High voltage transients can degrade power systems. The high data rates required in transient detection are too fast for current microprocessors to handle by themselves and still perform other data sampling and reporting functions at the desired rate. The occurrence of these transients is often intermittent and unpredictable.
The Transient-Current-Voltage (TCV) Module of the invention solves the problem of unattended detection, storage, and analysis of these transients. The Acquire/Trigger/Control/Interface (ATCI) chip is a component of the TCV and makes the TCV possible. When used in a system with a general purpose microprocessor, the ATCI chip makes possible the continuous real-time detection and storage of high voltage transients on any of three independent channels. The xe2x80x9cplug-inxe2x80x9d nature of the module makes it easy for the customer to upgrade an existing current-voltage monitor (CVM) with a TCV by simply replacing the module and downloading the main meter firmware.
Square D, the assignee, currently manufactures a CVM, known as CM4 meter. This invention adds transient analysis capability to an existing CM4 meter in a small, relatively low cost plug-in module and enhances the functionality of the CM4. It allows the customer to add transient analysis to the CM4 by simply purchasing the module and upgrading the CM4 firmware. It provides transient analysis capability to customers at significantly lower cost than competitive offerings. The CM4 can analyze data at a rate of 512 samples/cycle. The TCV can analyze data at a rate of 83,333 samples/cycle. Any customer who wants high speed transient analysis in addition to the present low speed analysis can use the TCV.
The TCV makes high-speed transient detection and storage possible as follows:
1. Provides an interface to a general purpose microprocessor for accessing data and status.
2. Detects transients on any combination of three channels by means of a user programmable voltage/duration triggering mechanism.
3. Uses two independent, switchable memory banks to allow continuous and simultaneous real-time storage and analysis of an incoming transient data stream. Real-time raw data is continuously loaded into one bank of memory while the general-purpose microprocessor simultaneously analyzes the previously acquired data in the other bank with no interruption in the incoming data stream. The two memory banks can be switched on command from the general purpose microprocessor and the roles of the memory banks reversed with no data loss. This technique allows long transients to be analyzed with no loss of data.
4. Provides memory storage for multiple trigger pickup and dropout points. This greatly speeds processing of the incoming transients.
5. Provides a First-In-First-Out (FIFO) and necessary handshake and control for communication with the main monitor.
Briefly, in accordance with the foregoing, an impulsive transient detection and data acquisition apparatus is provided for use with a power monitoring device having a processor for performing data sampling and reporting at a given rate. The coprocessor comprises a processor, an interface for accessing data from said processor, a plurality of channels for monitoring for transients and at least two independent, switchable memory banks for simultaneous real-time storage and analyses of an incoming transient data stream.
In another embodiment of the invention, a method of monitoring a power system to detect transient events, said monitoring method comprises accessing data from a processor, monitoring for transients, and performing simultaneous real-time storage and analyses of an incoming transient data stream using at least two independent, switchable memory banks.
In another embodiment of the invention, an impulsive transient detection and data acquisition apparatus for use with a power monitoring device having a processor for performing data sampling and reporting at a given rate, said coprocessor comprises means for processing data, interface means for accessing data from said processing means, means for monitoring for transients in a plurality of channels, and at least two independent, switchable means for simultaneous real-time storage and analyses of an incoming transient data stream.